Build quality of the CrossRoads MylarOne X3i and XBi is nothing short of pathetic. Cheapest materials used, and no quality control whatsoever. Yes, they sound amazingly good for a $60 phone, but that's no fun if they crap out after a few days or weeks.

The cable is an awful tube of stiff plastic with two painted wires inside. The outer tubing is not molded to the wires inside, but can move around freely. I've never seen a cable as bad as that. There's also no strain relief of any sort - just the outer tube glued to the little ball on the earphone. This little ball is a very sorry excuse for a strain relief. Furthermore, which is extremely important for a sturdy cable strain relief - the cable is not knotted inside the earphone housing, just the bare wires hanging loosely around in the shell.

Take a sharp knife, pry those hunks of junk open, and take a look for yourself.

See? No strain relief at all...

I've taken the far superior cable of an old version XB (not XBi) to put on the X3i. Nothing to de-isolate, the cables are simply painted. Remove the outer tubing and burn the paint off the cable tips with a soldering iron.

De-solder the old cables and clean the glue residue out of the housing (at the silver connections as well as at the cable entry hole).

Now solder the good cables onto the speaker drivers. Remember which earphone is left and right, and also which cable is the ground and the signal. Also make sure to slip the back part of the housing onto the cable before soldering!

Next you make the strain relief knot inside the housing - the most important part in prolonging the life span of the phones! How CrossRoads could release phones without that knot on the cable is absolutely insane...

Before you glue the housing together, make sure there's sound on both earphones, and the left and right signals are correct.

Take some good glue for the housing (not the wimpy crap CrossRoads uses). I use two component epoxy glue, that should last a lifetime. I put it in a vice, very carefully of course, to let it dry.

Voila, much better than new! Good thing I also got rid of the X3i's awful tiny 3.5mm plug in the process, and back to the proper one of the old X3/XB versions.